Thermostatic gas-valve mechanism.



Patented Apr. 3, 1917.

2 SHEETS-SHEET l.

n KIZ E E I? E KID Ew E7 E8 Kn U6 Ew E l K3 L I K2 m L5 K9 y 3 #Q "5 K8 NVENTOR Ji-l; ATTORNEY APPLICATION FILE JULY l5, 1912.

L. D. LOVEKIN.

IHERMOSTATIC GAS VALVE MECHAMSM.

APPLlc/moN man luLY l5, 1912. A 1,221,19?, Pntvntod Ain'. 1917. y 2 sHEE'rs-AsHEEr 2,

M ATTORNEY WITNESSES LUTHER D. LOVEKIN, OF PHILADELPHIA, PENNSYLVANIA.

THERMOSTATIC GAS-VALVE MECHANISIVI.

Specification of Letters Patent.

' Application led'July 15, 1912. Serial No. 709,355.

To all whom t may concern:

Be it known that I, LUTHER D. LovnnrN, a citizen of the Unitedl States of America, residing .in the cityand county of Philadelphia, in the State of Pennsylvania, have invented a certain new and useful Improvement in Thermostatic Gas-Valve Mechanisms, of which the following is a true and exact description, reference being had to the accompanying drawings, which form a' part thereof. p

yMy present invention relatesto `a thermostatic gas valve mechanism, es ecially adapted to automatically control the How of gas to the burner of a water heater-to maintain the temperature of thewater therein at or above a certain pre-determined minimum. The general object of the invention is to provide a simple, effective and reliable mechanism for the purposespecied. More specifically, one main object of the invention is.

to provide a thermostatically controlled mechanism utilizing the pressure of the gas supply system to operate 'a maingas valve, which will insure positive and substantial opening and closing movements of said valve. This l accomplish by the use of a ,pilot valve, directly controlled by the thermostatic mechanism, and actuated thereby to establish communication between the gas supply system and the pressure chamber of fluid pressure operating means for the main gas valve to open the -latter and to out oil such communication when the main gas valve should close. The closing of the main gas valve is brought about after communication between the supply system and pressure chamber is interrupted by reducing the pressure in said chamber. This reduction in pressure lmay be effected either by the use of a continuously open restricted leakage channel, or channels, leading from `said chamber or by the use of an exhaust port controlled by the pilot valve mechanism, or, advantageously, the provisions for obtaining a restricted'leakage from the chamber maybe combined with the pilot valve conclosing mo'vementof the main valve. Ad-

vantageously, the gas exhausted from the u pressure chamber is disposed of and utilized by passing it to the pilot burner which is constantly kept alight in the normal operation of the apparatus.

A further specific object of the invention is to provide mechanism of the character specied, which is simple in construction and comparatively cheap to manufacture,l and which is 'easy to assemble, take apart and adjust.V

v The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a port of this specification. For a better Imderstanding of the invention, however, and of the advantages possessed by it, reference should be made tothe accompanying drawings and descriptive matter in which l have illustrated forms in which the invention may be embodied.

Of the drawings,

Figure l is an elevation partly in section Fig. 2 is a sectional elevation of the fueli controlled mechanism proper shown in Fig. 1.

Fig. 3 is a view taken similarly to Fig. 2

' but on a larger scale and showing a portion only of the apparatus shown-by Fig. 2.

Fig. 4 isa sectional elevation of a modified form of the apparatus shown in Fig. 2.

Fig. 5 is a sectional elevation of a second modification of the apparatus shown in Fig. 2.

In the drawings, andI referring first to the construction shown in Figs. 1, 2 and 3, A represents a water heater, B the main gas burner for the heater, and C the main gas supply pipe. A pipe C1 connects the burner B to the main gas valve D, and the latter is connected'in turn to the supply pipe C. The valve D is controlled, as hereinafter explained in detail, by a thermostatic mechanism E, secured to the bottom of the heater, and comprising aportion extending into the heater, andcomprisingalso a pilot valve K, operated by the thermostatic mechanism. The casing of the main gas valveD is formed with an inlet chamber, D1 and an outlet chamber D2. These chambers are connected to the pipes C and C1, respectively, and are connected together by a port Da which is controlled by the conical valve member F, locatedon the outlet side of port D2. The stem l?1` of the valve member IF has a sliding bearing in the sleeve D1, carried by the valve casing D on the inlet side of, and co-axial with the port D2. The valve member F is formed at its outer end with a kerf F2 by means of which the valve stem may be held against rotation in the assembly and adjustment of the apparatus, and an aperture D5, normally closed4 by a removable plug is formed in the casing of valvevD to permit the insertion of the valve member F into and its removal from the'valve'casing when this is necessary. Advantageously, the valve member F, ,audits stem F1 are made of aluminum which permits the movable valve parts to be pf very light weight.

At its inner end the valve stem F1 is detachablysecured lto the center of a flexible diaphragm which is of circular formeand is clamped at its periphery. between the edges of conical shell-like portions D6 .and 4 A 1 K1 respectively, of the casings ofthe gas valve D and the pilot valve K. One side of the diaphragm H is thus exposed' to the pressure of the gas in' the inlet chamber D1 of the valve D, and the other side of the diaphragm is exposed to the pressure existing in the pressure chamber K2 of the valve K. The casing `of valve K has an inlet chamber K8 communicating with the pressure chamber K2,y through the port K4.

A threaded aperture, K11, is formed in the wall of the casilg K, at the opposite side of the chamber 2 rom'the port K1, and in axial alinement with the latter. This aperture receives the externally threaded tubular member K". The latter is formed with a spring chamber K8 o en at its upper end, and with a valve seat 2 atl the upper end of said spring chamber, and with a passage leading from the lower end of the springchamber and connected by the pipe C1, the free end of which serves as a pilot burner. The chamber K3 of the valve cas ing K is connected to the main gas supply ipe C by the pipe C2 and branch pipe C1.

he pipe C2 is also connected to the pilot burner through the cock C5. Communication between the supply chamber Ks and the intermediate chamber K2 and between the latter and the spring chamber K8 is controlled by valve members L and L1, respectively. These are located within the chamber K2 and are slidably mountedv on the valve rod M between the shoulders on the latter formed by the collar M1 pinned to the rod M, and by the nut M2 threaded on the lower end of the rod M. The valves L and L1 are at, all `times urged away from each other and into the positionn which they close the ports K4 and the mouth of the spring chamber Ks by an interposed spring L2. It will be apparent,-however, that when spring L2.

the valve rod is depressed collar M1 will engage the valve L and move it away from its seat, and that in this condition at the aperture the valve L1 will be seated. Similarly, when thevalve rod is elevated, the nut M2 will engage the valve L1, and lift it away from its seat, and at the same time the valve L will be held against' its seat by the In practice, I prefer to adjust the parts so that, as shown in Fig. 2, the valves L and L1 may both be seated at the same time, and a slight axial movement of the valve rod M away .from a neutral position is requiredto open either valve. In the practical use of my invention, I have found it 'highly desirable, if not absolutely essential, to make stuffing box provisions -such as are formed by the packing L3, and

the screw gland L4, to prevent leakage through the valve member L, along the rod M. I also consider it advantageous to employ similar stufling box provisions in connection with the valve L1, although I prefer to provide for a restricted leakage outvof the chamber K2, such as may advantageously be obtained by forming a small hole L5 through the valve member L1.

As shown, a spring Ms constantly acts on the valve rod M in the direction tending to lift the valve member L off its seat. This spring is lopated in the spring chamber K8, and `extends between the bottom of that chamber and the nut M2 threaded on the lower end of the rod M. The spring Ma should be under tension sufficient to overcome the tension of the spring L2 when occasion permits.

" The casing K is formed above the chamber K3, with a tubular portion K1o cut away to provide finger holes K11, and tern'iinatiug at its upper end, in a machined end surface against which a shoulder E1 of a tubular body member e is clamped by the apertured cap member K12 screwed to the externally threaded upper end ofthe casing K and nor- 4mally locked against displacement by the locking screw K13. This arrangement permits the casing K to be adjusted angularly with respect to the body member e in assembling the apparatus and taking it apart without disturbing the adjustment of the thermostatic mechanism proper. The member e is threaded at its upper end into the lower end wall of the heater and has a tubular member E2 threaded into its upper end. The member E2 extends into the interior of the heater and is closed at its upper end by the cap member E11.

The valve actuating member roper com-V prises a tubular art E1, locate wlthin the tubular member 2 and provided at its upper end with a piece E5 adapted to engage -the cap E3, and, at its lower end, with an end member E", having a sliding t in the member e. A bolt E7 threaded into a nut -the bolt E'r in the nut E8.

-rotating the nut E8 inv its threaded socket afterwhich the nut and end member E are locked together by the set screw E14. A further adjustment may then be had by rotating To prevent an undue elongation of the valve actuating member after the nut E2` is 'locked to the end member E, the bolt E7 has a collar E11 pinned to its upper end. v

A p1n E12 secured in the lower end of the body member e operates in conjunction with a guide surface formed on the end member E6, to prevent relative rotationA between'the end member E6 and body member e which, if permitted, interferes with the ready'adj ustment of the apparatus. `Passages E13 are formed in the body member to permit of a circulation of air through the space surrounding the member E4, which tends to cool the` latter, therefore adding to the sensitiveness of j the thermostatic actuating mechanism. The tubular member E4 may preferably be made of Steel which has a relatively small coefficient of thermal expansion, while the tube E2 is made of brass, copper or other material having a 'relatively high coeiicient of thermal expansion.

In the' arrangement shown in Figs. 1 and 2 gas is supplied to the chamber K8 of the pilot valve mechanism from the supply piping C through the pipe C2 and the branch pipe C2, which is secured in a suitable aperture K15, opening lfrom the chamber K3. The waste'gas from the pilot valve mechanism is carried away by the pipe C4 coupled tothe member K1 andopening to the interior of the latter through the aperture in its lower end. Advantageously, as shown, the pipe C4 terminates at its free end in proximity to the main gas burner B, and, in practice, I prefer as shown `that the up er end of th'e pipe C4 shall serve as the pilot burner by which a pilot flame for ignlting the gas issuing from the main burner is constantly kept alive. For this purpose, I have connected the pipe C4 to the pipe C2 through a suitable'regulating valve C", as shown in Fig. 1, which permits of a constant restricted iow of' gas to 'the burner endof the pipe C4. It will be understood that the arrangement should be such that the restricted How of gas into pipe C permitted by the valve C, is not great enough to create a pressure in the pipe C4 appreciably higher than the pressure of the atmosphere.

In operation, the yexpansion of the tubular part E2 relative to the' tubular member E4, occurring when the water `in the heater reaches'a certain temperature fixed by the adjustment of the apparatus, permits the pilot rod M to be moved by the spring M3 into the position in which the valve L closes the portV K4, so that gas `cannot then pass intoethe pressure chamber K3. As soon as communication is thuscut 0E between the supply chamber K2 and the pressure chambe-r K2 ofthe valve K, the'pressure in the chamber K2 quickly falls to the pressure of the atmosphere owing to the leakage con- 'stantly taking place through the restricted I leakageport L5. When the pressure in chamber Kis thus reduced, the valve F is closed and held closed by the pressure of the gas 'supplysystem. This pressure, -while acting directly against the valve F in a direction. tending to open the latter, acts in .the opposite `direction against .the substantially larger area of the left-hand side of the diaphragm H, as seen in Fig. 2.

' When the temperature of the water in the tank A falls below that which the apparatus is adjusted to maintain, the resultant contraction of the tube E2 causes the valve rod M to be-moved downward, and thereby open the valve L. This permits gas from the supply system toiowfrom the supply chamber K3 of the pilot valve mechanism into pressure chamber K2,V thereby raising the pressure in the latter to that of the main gas supply system. This equalizes the pressure on the two sides of the diaphragm H and the gas pressure acting directly against the inlet side of the valve F causes the latter to begin to open. As the valve F begins to open, the pressure on the outlet side of the valve rises and the pressure on the inlet side may fall.' This diminishes the pressurediii'erential act-` ing directly on the valve F but is more than compensated for, and a rapid and complete opening movement of the valve is insured by the consequent decrease in the pressure acting against the left-hand side of the diaphragm H. `When the valve F thus opens,

ein

gas is supplied to the burner B through the pipe C1. The gas issuing from the burner B is instantlyignited by the flame frpm the.

pilotl burner and the iame from the main burner continues until the water in the tank is again raised to the desired temperature, whereupon the resultant expansion of the thermostatic member E2 again permits the valve rod to be moved by thespring M3 into the position shown in Fig. 2 in which the valves L and L1 are both seated.

`With the apparatus shown in Fig. 2, gas is constantly leaking from the chamber K2 through the port L, while the main gas valve is open. This gas is not wasted, .however, since it is burned at the pilot burner and the heat resulting from its combustion is added to the heat then given on' at the main burner in heating the water -in the tank A. As a matter of fact,'however, the amount of gas leaking through the port L5 in the normal operation of the apparatus, is

' so small that its heating effect is practically in closing the main gas valve, but a slight expansion of the tube E0 beyond that re quired to permit the seating of the-valve L will result in permitting an upward movement of the valve rod M under the action vof its spring M3 sufcient to lift the valve L1 off its seat, andthereby connect the chamber K2 freely with the pipe C1 running to the pilot burner.

While I consider it desirable, in most cases, to provide a constantly open restricted leakage passage from the pressure chamber K2, since with it no increase in the temperature of the water heated beyond that required for' the seating of Ithe valve L is necessary to bring about the closure of the main gas valve, the temporary closure or permanent omission of this port does not destroy the material effectiveness of the, apparatus.

In' Fig. 4, I have shown a modification of the apparatus of Figs. 1, 2 and 3, in which certain changes in construction and arrangement are made In particular, the constantly open leakage channel from the pressure chamber K2 is dispensed with, though such a channel may well be used in this construction also. The main gas valve DA and the pilot valve mechanism KA of Figs. 3 and 4 correspond in most respects to the valve mechanism D and K of the form first described, and similar parts in the two constructions are designated in the drawings by similar reference letters.

In the construction shown in Fi 4, the removable part K7 of Fig. 2 is rep aced by an externally threaded tubular fitting K having its open upper end adapted to form a seat for the lower pilot valve member, L11, and having its lower end closed by a cap K". The member K70 is formed with ports K72 connecting its interior with an outlet annular channel K73 formed in the casing of valve KA. The fitting l 70 is in threaded engagement with the casing pf valve KA both above and below the channel K13, and is adapted to be axially adjusted to the different operative positions. K74 represents a lock nut for securing the member K10 in any desired adjustment. K"5 represents' a threaded socket opening from the channel K"8 and into which the pipe C4 may be secured. As shown in Fig. 4, the main gas valve member FA controlling the port D3 is in the form of a disk, separable from but normally clamped to the valve stem F10 and the latter is formed with an extended outer end F10, having a sliding bearing in the passage D50 formed in the plug, closing the aperture D in the casing of valve DA. The outer end of the passage D00 is normally closed by the small plug D01.

The upper' and lower pilot valve members L10 and L11 may be identical with the valves L and L1 first described, but, as shown, do not have stuffing box provision. As shown,

the valve rod MA is formed at its lower end with an integral enlargement M10, forming a collar adapted to engage the under side of the valve L11. Above the valve L10 the rod MA is formed with a reduced threaded portion to receive a collar for engaging the upper side of the valve member L10. This collar is formed by the nut M12 and the lock nut M13. At its lower` end the rod MA is further enlarged to provide a piston-like guide M5. The spring Ms extends between the guide M5 and the cap K11. The operation of the; apparatus shown in Fig. 4 will be readily apparent without further explanation from what has already been said.

In the modification shown in FiO. 5, the casings of the main valve BB and of the pilot valve mechanism KB do not differ from thecorresponding parts of the mechanism shown in Fig. 2. In Fig. 5 communication between the supply chamber K8 and the pressure chamber K2 of the pilot valve mechanism, is controlled by a valve memberl L20which may be integrally connected to the valve rod MB, and the aperture at the bottom of the chamber K2 closed in Fig. 2 by the member K7, is closed by a plug K10, formed with a guide socket K11 for the lower end of the valve rod MB. The valve member L20 is constantly urged toward its seat by the spring M10 interposed between it and the lug K0. With the construction shown in *ign 5, the necessary reduction in pressure in the chamber K2 following the seating of the valve L20 is brought about by the leakage through the leakage channel F20 and F21, formed in the valve stem F10 of the main gas valve FB. As shown, the portion F20 of this leakage channel is relatively large in diameter, while the short portion F21 is restricted and may be of sub-v stantially the same diameter as the port L of the construction first described. The outer end of the valve stem F10 has a sliding bearing in the passage D02 formed in the plugclosing the valve casing aperture D, and this plug is provided with an external mamar hollow boss D5s connecting with the passage D22 and externally threaded for connection to the pipe C1 running to the pilot burner.

It will be 'apparent that the apparatus shown in Fig. 5 while simpler than that shown in Fig. 2, will operate in exactly the same manner, so long as the leakage port L5 of the apparatus shown in- Fig. 2 1s effective to bring about the reduction in pressure in chamber K2 necessary for 'the closure of the main gas valve. 'Ihe apparatus shown in' Fig. 5 is open to the objection,

gas valve shall be horizontal and independ-- -ent of action of gravity, and I prefer that,

the main gas valve and its valve stem `shall be made of aluminum to decrease the weight of the moving parts. 'Ihe horizontal arrangement of the main gas valve is of particular importance in the form of the apparatus shown in Fig. 5, because with lthis disposition of parts the liability of the restricted leakage channel to clog is greatly diminished. I have demonstrated by extended practical `use of the apparatus disclosed herein, that positive and rapid openin and closing movementsof-the main gas va ve may readily be obtained, notwithstanding the comparatively small difference between the pressure of the atmosphere and the pressure of the gas supply system. It will be obvious to those skllled in the art that the apparatus disclosed is compact and comparatively easy and inexpensive to manufacture, and that the various parts may be assembled, taken apart, adjusted and repaired With ease. With the particular pro'- visions for adjustment disclosed an approximate adjustment of the length of the thermostatic valve actuating member formed by the ports E4, E8 and E may be obtained when the ap aratus is voriginally installed, and after belng so installed, a further adj ustment within comparatively narrow limits can readily be had by lrotation ofthe bolt E7, the vlmurled head of which is accessible for this purpose, through the single opening K11. With this arrangement, the initial adjustment should be so eli'ected that the further adjustment obtained by the rotation of the bolt ET cannot result in the production ofexcessive temperatures within the heater A. As both the collar E11 and the locking screw Eo by which the nut ES is screwed to the end E are inaccessible in the assembled apparatus, the ordinary unskilled attendant, while readily able to adjust the apparatus to vary the temperature'of the water heated within the range of adjustment obtainable by rotating bolt E7, yis prevented from adjusting the apparatus in such manner as to obtain a dangerous or objectionably high temperature in the heater. i

While in accordance with thel provisions ofthe statutes, I have illustrated and described the best forms of my invention now known to. me, it will be' apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention, and that under some conditionscertain yfeatures of my invention may be used without a corresponding use of other features.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In combination a main gas burner, a gas supply system, a main valve controlling the vflow of gas from said system to said burner, and operating provisions for said main valve including a pressure chamber, a waste gas conduit leading from said chamber and` a thermostatically actuated valve mechanism adapted to connect said chamber alternately to said gas supply system and, to said waste pipe.

2. In combinatlon a main gas burner, a gas supply system, a main valve controlling the flow .of gas therefrom to said burner, and operating provisions for said main valve including a pressure chamber, a normally open restricted leakage vent leading from said pressure chamber, a second gas escape vent leading from said pressure chamber, and a thermostatically actuated valve mechanism adapted to cut oli and establish communication between said pressure chamber and sai'd system as the temperature to whichsaid thermostatic mechanism is subjected approache's and recedes from one limit and adapted to open said second vent when said temperature receding 'from said limit reaches a second predetermined limit.

3. A thermostatic valve mechanism for `controlling the supply of gas from a gas 4. A thermostatic valve mechanism for controlling the supply of gas from a gas supply system to a gas burner comprising in combination,a main gas valve having inlet and outlet chambers and a port connecting them, a Valve member controlling said port and located onthe outlet side thereof, a pilot valve mechanism comprising a pressure chamber and thermostatically actuated means adapted to alternately connect said pressure chamber tosaid gas supply system and to waste on predetermined variations in the temperature to which said thermostatically actuated means is exposed, and a flexible diaphragm separating said pressure chamber from the first mentioned inlet l chamberI and connected to and operating said valve member.

A thermostatic valve mechanism controlling the supply of gas from a gas supply system to a gas burner comprising in combination, a main gas Valve having inlet and outlet chambers and a port connecting them, a valve member controlling said port and located on the outlet side of the outlet thereof, a pilot valve mechanism comprising a pressure chamber, a normally open restricted leakage Ventopening therefrom, a second gas escape vent opening from said pressure chamber, and thermostatically actuated means adapted to cut ofi' and establish communication between said pressure chamber and said gas supply system as the temperature to which said thermostatic mechanism is exposed approaches and recedes from one limit and adapted to open said second vent when .said temperature receding from said limit reaches a second pre-determined limit.

6. In combination a main valve and fluid pressure operating means therefor including a chamber and Vinlet and outlet passages through which a fluid under pressure is admitted to and exhausted from said chamber to thereby open and close said valve and a thermostatically actuated valve mechanism comprising separate valvev members controlling said passages, resilient means tending to separate said valve members and cause them to seat, and a valve operating member on which said valves are slidingly mounted, said operating member having provisions adapted to engage one or the other of the valves and move it away from its seat against the action of said resilient means accordingly as said operating member is moved in one direction or the other.

7. In combination a main valve and fluid ,i pressure operating means therefor, including a chamber into which a fluid under pressure is admitted and from which it is exhausted to open and close said valve, and a thermostatic actuated mechanism controlling the admission to and exhaust from said chamber, said mechanism including separate inlet and outlet valve members resilient means tending to separate said members and cause them to seat, and a valve operating member on which said valves are slidingly mounted, said inlet valve member having stuffing box provisions for preventing leakage along said rod, and said operating member having provisions adapted to engage one or the other of the valves and move it away from its seat against the action of said resilient means accordingly as said member is moved in one direction or the other.

8. In combination a main valve and fluid pressure operating means therefor, including a chamber into which a fluid under pressure is admitted, and from which it is exhausted to open and close said valve, and a thermostatically actuated mechanism controlling the admission to and exhaust from said chamber, said mechanism including separate inlet and outlet valve members, resilient means tending to separate said members and cause them to seat, and a valve operating member on which said valves are slidingly mounted, said valve members having stufling box provisions for preventing leakage along said rod, and said operating member having provisions adapted to engage one or the other of the valves and move it away froln its seat against the action of said resilient means accordingly as said member is moved in one direction or the other.

9. A thermostatic valve mechanism comprising in combination a main valve casing formed with inlet and outlet chambers and with a port connecting them and with an aperture opening from said inlet chamber in line with said port and with a flange surrounding said aperture, a pilot valve casing formed with a pressure chamber and with an aperture opening therefrom and with a flange surrounding said aperture, a flexible diaphragm clamped at its margin between the flanges of the main and pilot valve casings and separating said inlet chamber from said pressure chamber, a valve controlling said port and operated by said diaphragm and thermostatically actuated means for arying the pressure in said pressure cham- 10. A thermostatic valve mechanism adapted to control the heating of a Water heater and comprising in combination a casing part adapted to be attached to the wall of the heater, and having a tubular extension which then projects 1nto said heater, a valve actuating member comprising one part located Within said casing part and tubular extension with its inner end engaging the latter, and having its outer end in sliding engagement with said casing part and formed with a threaded socket, a second threaded part screwed into said socket, means normally concealed by said casing part for locking said member in said socket in any desired adjustment, a third part in threaded engagement with said second part, and means for limiting ther extent to which the length of said valve actuating member may be adjusted by rotating said third part relative to said second part.

1l. A thermostatic valve actuating member comprising an elongated body portion, a second part, means for locking the said second part and body portion together in adjusted relation, a third part in threaded engagement With said second part and means limiting the extent to which said actuating member may be elongated by the threaded adjustment of said third part relative to the said second part.

12. A thermostatic valve mechanism com-l prising in combination a part formed with a sleeve bearing for a valve actuating member and a valve actuating member comprising one part slidingly received in said sleeve bearing and formed With a socket, a second part entering said socket and adjustable therein, a locking device for securing said rst and second parts together and normally covered by said sleeve bearing, and a third part in threaded engagement with and thereby adjustable With respect to said second art. P 13. A. thermostatic valve mechanism adapted to control the heating of the Water heater comprising in combination a casing part adapted to be attached tothe Wall of the Water heater and comprising a tubular portion which then projects into the heater.

ing formed with a t readed, socket; and a third part having a ythreaded portion vscrewed into and extending through said second part, and means secured in the inner end of said third part and adapted to'engage l the inner end of said second part and thereby limit the extent to Which said valve actuatin member may be elongated by rotating said third part relative to said second part.

LUTHER D. LOVEKIN. Witnesses:

ARNOLD KATZ, lD. STEWART. 

